Elevated temperature tension, compression and creep-rupture behavior of (001)-oriented single crystal superalloy PWA 1480

Tensile and compressive flow behavior at various temperatures and strain rates, and tensile creep rupture behavior at 850 and 1050 C and various stresses were studied for (001)-oriented single crystals of the Ni-base superalloy PWA 1480. At temperatures up to 760 C, the flow stress is insensitive to strain rate and of greater magnitude in tension than in compression. At temperatures of 800 C and above, the flow stress decreases continuously with decreasing strain rate and the tension/compression anisotropy diminishes. The second stage creep rate and rupture time exhibited power law relationships with the applied stress for both 850 and 1050 C, however with different stress dependencies. The stress exponent for the steady state creep rate was about 7 at 1050 C, but much higher at 850 C, about 12. Directional coarsening of the gamma' phase occurred during creep at 1050 C, but not at 850 C

Computational interior ballistics modeling

Interior ballistics are the events in a gun system that determines the performance of any gun design. In order to efficiently design any gun system the internal ballistics should be understood to minimize energy losses and correctly define design parameters. The goal of this computational model is to develop a ballistics model to aid in gun design. A computational analysis of the dynamics events aids in the design of the gun system by providing output information such as pressure, velocity, charge burnout, and projectile distance versus time profiles. By applying the chemical and physical parameters of the propellant, gun breech geometry, projectile mass and gun barrel parameters, one can iterate through design parameters in an attempt to improve gun performance. There will be several computational models describing the main program being a lumped parameter internal ballistics analysis. The muzzle velocity of the model has been validated with empirical testing to at least one gun system and being applied to other gun systems for further validation on different designs. The validation of the muzzle velocity and breech pressure will build confidence in the model and allow for the model to be further developed into a more user friendly program

The environmental dependence of neutral hydrogen content in spiral galaxies

We present a study of the relationship between the deficiency of neutral hydrogen and the local three-dimensional number density of spiral galaxies in the Arecibo catalog of global HI measurements (Springob et al. 2005). We find that the dependence on density of the HI content is weak at low densities, but increases sharply at high densities where interactions between galaxies and the intra-cluster medium become important. This behavior is reminiscent of the morphology-density relation (Dressler 1980) in that the effect manifests itself only at cluster-type densities, and indeed when we plot both the HI deficiency-density and morphology-density relations, we see that the densities at which they "turn up" are similar. This suggests that the physical mechanisms responsible for the increase in early types in clusters are also responsible for the decrease in HI content.Comment: To appear in AIP Conference Proceedings, "The Evolution of Galaxies through the Neutral Hydrogen Window", Feb 1-3 2008, Arecibo, Puerto Rico, eds. R. Minchin & E. Momjian. 3 pages, 2 figure

Thermomechanical deformation behavior of a dynamic strain aging alloy, Hastelloy X

An experimental study was performed to identify the effects of dynamic strain aging (solute drag) and metallurgical instabilities under thermomechanical loading conditions. The study involved a series of closely controlled thermomechanical deformation tests on the solid-solution-strenghened nickel-base superalloy, Hastelloy X. This alloy exhibits a strong isothermal strain aging peak at approximately 600 C, promoted by the effects of solute drag and precipitation hardening. Macroscopic thermomechanical hardening trends are correlated with microstructural characteristics through the use of transmission electron microscopy. These observations are compared and contrasted with isothermal conditions. Thermomechanical behavior unique to the isothermal database is identified and discussed. The microstructural characteristics were shown to be dominated by effects associated with the highest temperature of the thermomechanical cycle. Results indicate that the deformation behavior of Hastelloy X is thermomechanically path dependent. In addition, guidance is given pertaining to deformation modeling in the context of macroscopic unified theory. An internal state variable is formulated to qualitatively reflect the isotropic hardening trends identified in the TMD experiments

Bob Delvin

Delvin relates the story of Clayton Highum\u27s dismissal and Myers\u27 subsequent offer to have Delvin serve as interim University Librarian. He uses other incidents of Myers\u27 interactions with him and a School of Music faculty member to illustrate Myers\u27 knowledge of music and use of others\u27 knowledge as a means to achieve goals. Delvin speaks of Myers\u27 collecting as artifactual rather than intellectual and recounts how Myers acquired a collection of sheet music

Robert Bray

Bray and Myers went on book buying trips in the local area. Recalls that Myers used the word sickness to describe himself but with some level of humor. Discusses different ways Myers\u27 collected and differences from his own methods and knowledge of books. Bray also shares views on the effect Myers\u27 personal characteristics had on IWU and individuals

Priority Water Issues in the Pacific Northwest

We developed and conducted a region-wide survey to collect base line information documenting public awareness, attitudes, and priorities about water issues in the Pacific Northwest. The vast majority (over 90%) of survey respondents considered clean drinking water, clean groundwater, and clean rivers very or extremely important issues. Over two-thirds of survey respondents considered having enough water for economic development, prevention of salmon extinction, wetland protection, watershed restoration, water for power generation, and water for agriculture to be high priority issues. The results from this survey will be used to target our regional programming efforts over the next 5 years

Failure Analysis of Geothermal Water System Components

The premature failures of a valve head bolt, buried pipe, and in­home heat exchanger from a local geothermal water system have motivated a forensic approach to finding the mechanisms of these failures. These issues can potentially harm water distribution and damage homes, a concern leading to a collaboration between the overseeing district board and a senior project team from Boise State University’s Materials Science and Engineering program. Failure analyses consisted of visual inspection, scanning electron microscopy (SEM), x­ray fluorescence spectroscopy (XRF), x­ray diffraction (XRD), electrochemical testing, and inductively­coupled plasma mass spectrometry (ICP­MS). SEM coupled with energy­dispersive spectroscopy (EDS) were used for basic chemical analysis. XRD of corrosion products correlated with EDS data to determine molecular species. Visual inspection and SEM of the bolt and pipe failure sites and cross­sections developed information on failure propagation and possible chemical influences. Failure site isolation for the heat exchanger indicated that the pipes failed near braze sites, with the braze materials having been identified by XRF. ICP­MS analysis of the geothermal water aided our electrochemical testing of the corrosion behaviors likely contributing to failure. Suggested alterations to material selection and treatment might prevent similar component failures moving forward

Effectiveness of Three Foodservice Equipment Training Interventions for Food and Nutrition Students

This study evaluated students’ (N = 65) reported knowledge, competence, and comfort in using foodservice equipment, as well as confidence in training others after completing one of the following interventions: 1) two food/nutrition courses, and foodservice supervised practice rotations, 2) equipment introduction, and competency exam, and 3) equipment training, practice lab, and competency exam. Foodservice operations and dietetics programs should consider implementing Intervention 3 because there was a significant increase in knowledge, competence, comfort, and confidence using equipment from pre- to post-intervention, it yielded the highest post-intervention scores, and most students received \u3e86% for their actual skill